Other words with similar meanings include: isolex, an isogloss for a particular item of vocabulary, and isophone, an isogloss for a particular feature of pronunciation.

The distribution of names of carbonated beverages in the USA can be divided using isolexes – in some areas the usual name for such drinks is soda, in some it’s pop, and in others it’s cola or coke. In the UK we call such drinks pop or soft drinks.

The phenomenon of isoglosses is discussed in the Linguistics books I’m currently reading and I like the sound of the word. This word, and the related words, also illustrate one of the advantages of being familiar with the Greek roots of English words. Now I know that iso(s) means equal, words using this prefix are slightly easier to understand.